Efficient packaging of all subsystems is paramount in present day air vehicles. As a result many landing gear systems use complex, non-planar, drag or retraction linkages to rotate the wheel into a compact orientation that allows for efficient packaging. One example of a system is used on an F-16 aircraft nose landing gear in which a drag brace must rotate about an axis perpendicular to the retraction axis, resulting in non-planar retraction. Other examples are described in U.S. Pat. Nos. 4,984,755 and 3,086,733 that use wheel planing but do not allow steering of the front wheel when extended.
A further example is described in U.S. Pat. No. 2,371,699 ('699) in which the wheel is planed upon retraction and the wheel can be steered when extended. One failure mode of the landing gear shown in '699 is that the actuator can fail either disallowing retraction or, if failure occurs when the gear is stowed, possibly locking or wedging the landing gear inside the landing gear stowage compartment so that the gear cannot be extended.